What is the maximum allowable blood alcohol concentration for pilots?

The maximum allowable blood alcohol concentration (BAC) for pilots is 0.04%. This regulation is set by the Federal Aviation Administration (FAA) to ensure the safety of both pilots and passengers, as alcohol can impair cognitive and motor functions, which are crucial for safe flight operations. The 0.04% limit reflects the need for pilots to maintain a high level of alertness and judgment when flying.

Pilots are also subject to additional regulations regarding alcohol consumption; they must not operate an aircraft within eight hours of consuming alcohol (known as the "bottle to throttle" rule) and are expected to be free from any effects of alcohol while on duty. This strict standard aims to minimize the risk of accidents due to impaired pilot performance.